EP1864180A2 - Focalisation simultanee spatio-temporelle d'impulsions de l'ordre de la femtoseconde - Google Patents

Focalisation simultanee spatio-temporelle d'impulsions de l'ordre de la femtoseconde

Info

Publication number
EP1864180A2
EP1864180A2 EP06736409A EP06736409A EP1864180A2 EP 1864180 A2 EP1864180 A2 EP 1864180A2 EP 06736409 A EP06736409 A EP 06736409A EP 06736409 A EP06736409 A EP 06736409A EP 1864180 A2 EP1864180 A2 EP 1864180A2
Authority
EP
European Patent Office
Prior art keywords
spatial
temporal
pulse width
focusing
excitation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP06736409A
Other languages
German (de)
English (en)
Inventor
Guanghao Zhu
Chris Xu
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cornell Research Foundation Inc
Original Assignee
Cornell Research Foundation Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Cornell Research Foundation Inc filed Critical Cornell Research Foundation Inc
Publication of EP1864180A2 publication Critical patent/EP1864180A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B21/00—Microscopes
    • G02B21/06—Means for illuminating specimens
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B21/00—Microscopes
    • G02B21/16—Microscopes adapted for ultraviolet illumination ; Fluorescence microscopes

Definitions

  • the present invention relates in general to a method and apparatus for simultaneous spatial and temporal focusing of femtosecond pulses to improve the axial confinement and thus signal-to-background ratio (SBR) in multiphoton imaging techniques, such as microspcopy, endoscopy, spectroscopy, fluorescence microscopy, second harmonic microscopy, etc.
  • SBR signal-to-background ratio
  • This is achieved by spatially separating spectral components of pulses and recombining these components only at the spatial focus of an imaging system.
  • the temporal pulse width becomes a function of distance, with the shortest pulse width confined to the spatial focus.
  • MPM Laser scanning multiphoton microscopy
  • the present invention fulfills the foregoing need through provision of a technique for simultaneous spatial and temporal focusing of femtosecond pulses in multiphoton imaging.
  • This concept is realized by spatially separating spectral components of optical radiation pulses into a "rainbow beam" comprised of a plurality of spaced, preferably parallel beams of different wavelengths and recombining these components only at the spatial focus of an imaging system.
  • the temporal pulse width becomes a function of distance, with the shortest pulse width being confined to the spatial focus. This will improve the SBR by reducing the background excitation while maintaining the signal strength. This is because the efficiency of multiphoton excitation, which is a nonlinear process, depends strongly on the excitation pulse width (r) .
  • the excitation efficiency varies as ⁇ " 1 for two-photon excited fluorescence.
  • an extra degree of confinement for the excitation can be achieved if one can create a temporal focus where the pulse width varies along the propagation direction and the shortest pulse is only achieved at the focal point.
  • a chirp-free input rainbow beam is generated by first divergently separating the different spectral components from a mode-locked Ti:Sapphire laser using a reflective grating and then recollimating them using a cylindrical lens.
  • the geometric dispersion caused by the grating is automatically canceled after the process of recollimation and therefore the rainbow spectrum after the cylindrical lens is chirp-free.
  • the simultaneous temporal and spatial focusing effect is then realized by passing the rainbow beam through an objective lens, which focuses the beams both temporally and spatially at a focal point.
  • the second condition if a chirp-free spectrum of the rainbow beam can be produced at the back aperture of the objective lens, then from the optical path argument, the required chirp-free condition can be re-achieved after the objective but only at the focal point. Since the realization of the above two conditions is restricted at the focal volume, it then follows that the temporal focusing effect will occur only at the vicinity of the focal point.
  • the present invention can also be employed to provide remote axial scanning of the maximum signal excitation plane for wide-field nonlinear microscopy, which is a practical concern in the design of a nonlinear microscopy system.
  • the simultaneous spatial and temporal focusing technique of the present invention when operated in the wide-field mode, provides a way to perform the axial scanning of the maximum signal excitation plane in the axial direction. Wide-field operation removes the spatial focusing and therefore inside the focal volume illumination field is only temporally focused. This temporal focusing is achieved because different colors are spatially separated, i.e. the effect of geometrical dispersion.
  • the axial position of the maximum signal excitation plane shifts to the position where the input spectrum chirp is canceled by the geometrical dispersion, i.e. the position where the pulse temporal width is shortest.
  • Another application of the present invention is for automatic dispersion compensation in wide-field nonlinear microscopy based on a single-core fiber. Since short pulses are required at the sample end, due to the existence of relatively large fiber dispersion, regular methods typically require pre-dispersion compensation to prevent pulse broadening.
  • the fiber-delivery of ultrashort pulses is immune to the fiber chromatic dispersion.
  • the simultaneous spatial and temporal focusing technique intrinsically inherits the geometrical dispersion into the system as a result of wavelength spatial separation.
  • the dispersion accumulated through the propagation inside the fiber will be automatically compensated by shifting the temporal focal plane away from the geometrical optics one.
  • FIG. 1 is a schematic illustration showing the concept of simultaneous temporal and spatial focusing of femtosecond pulses in accordance with the concept of the present invention
  • FIG. 2 is a schematic illustration of an multiphoton imaging system that can be employed to implement the concept of the present invention (in the line-scanning mode) in accordance with a preferred embodiment thereof;
  • FIG. 3 are graphs showing auto-correlation traces of the measured pulse at different sample positions for an experiment conducted using the system of FIG. 2, with FIG. 3(a) showing the trace at the focal plane of the objective and FIG. 3 (b) showing the trace at a point 275 ⁇ m away from focal plane.
  • the inset inside trace (a) shows the interference fringes at the vicinity of zero time delay;
  • FIG. 4 is a graph illustrating the measured (solid square) and theoretically calculated (line) pulse width as a function of sample position for the experiments conducted with the system of FIG. 2, where the location of the focal plane of the objective lens is set to be zero;
  • ⁇ is the excitation wavelength
  • n is the refractive index of the medium
  • NA is the numerical aperture of the objective lens.
  • an extra degree of confinement for the excitation can be achieved if a temporal focus can be created where the pulse width varies along the propagation direction and the shortest pulse is only achieved at the focal point.
  • Such a technique will improve the SBR by reducing the background excitation while maintaining the signal strength.
  • FIG. 1 The basic principle for the simultaneous temporal and spatial focusing is illustrated in FIG. 1.
  • Spatial focusing is still achieved by passing the light through an objective lens. However, instead of keeping all the spectral components well overlapped in space during the focusing process, they are first separated spatially and are then recombined only at the focal point. More particularly, the system input is a rainbow-like superposition of many parallel optical beams of which the center positions are linearly displaced according to their wavelengths. The spectrum of the input is assumed to be chirp-free. After passing through a regular objective lens, the rainbow beam is then focused and recombined in space. Temporal focusing is achieved because of the reduced spatial overlapping and the non-zero geometric dispersion outside the focal volume.
  • the steps of the calculation are as follows: first assume that the input beam profile at the back aperture of the objective can be written as a superposition of many monochromatic, spatially transform-limited Gaussian beams, of which the center positions are linearly displaced according to their wavelengths. It is further assumed that the optical spectrum of the input waveform at the back aperture of the objective is chirp-free and has a Gaussian spectral profile. Then, for each monochromatic Gaussian beam, calculate the evolution of the spatial beam profile analytically using the standard paraxial propagation method. Finally, evaluate the performance of the simultaneous temporal and spatial focusing by summing up all the monochromatic contributions. It should be noted that from FIG. 1, since the spatial coupling only happens between x and z directions, the dependence of the beam profile on the variable y is therefore dropped in the analysis.
  • the input beam amplitude A 1 (Xj) is first written at the back aperture of the objective lens as a superposition of many spatial Gaussian beams, of which the center positions are linearly displaced according to their wavelengths,
  • V2 In 2 • s is the FWHM diameter of each monochromatic beam, a is a proportionality constant and a ⁇ A ⁇ is the linear displacement of the beam center at the offset frequency of A ⁇ . Because it is assumed that the input beam profile is a superposition of many spatially transform-limited and temporally chirp-free beams, both ⁇ and s are then treated as real numbers in these calculations.
  • n , _ -V ⁇ « ⁇ +, /,. ⁇ ⁇ -(z-/) (4-2)
  • the pulse width will be the shortest at the focal point.
  • the FWHM pulse width of 2V21n2 / ⁇ at the focal point is the transform-limited value for a Gaussian spectrum with a FWHM bandwidth V21n2 • ⁇ , indicating that the pulses at the focal point are once again chirp-free.
  • m becomes a large complex number.
  • the temporal pulse width increases quickly and the pulses are highly chirped. Therefore, true simultaneous spatial and temporal focusing is obtained.
  • the system 100 includes a scanning mirror 101 for receiving a pulsed optical radiation beams from a laser 102 or other suitable pulsed optical source and directing the beam through first cylindrical lens 104 to a grating 106.
  • the grating 106 separates the incident beam into a rainbow beam 108 including a plurality of separate beams, each of a different color or wavelength.
  • the rainbow beam is then passed through another cylindrical lens 110, which collimates the beams thereby making them parallel and evenly spaced.
  • the spaced beams are then incident on an objective lens 112, which then focuses the beams at a focal point as illustrated in FIG. 1.
  • a dichromatic mirror 114 receives the detected fluorescence from a sample (not shown) at the focal point and directs it through a low NA lens 116 to a CCD array 118 or other suitable detector.
  • FIG. 4 shows the measured temporal pulse width (solid squares) at various distances away from the focal plane by translating the thin Rhodamine B sample.
  • PWSF pulse width stretching factor
  • the present invention can also be employed to provide remote axial scanning of the maximum signal excitation plane for wide-field nonlinear microscopy.
  • One practical concern in the design of nonlinear microscopy system is the ability to perform remote scanning.
  • Other than traditional remote scanning technique, which are typically realized by adjusting the spatial wave-front profile, simultaneous spatial and temporal focusing technique when operated in the wide-field mode, provides another way to perform the axial scanning of the maximum signal excitation plane in the axial direction.
  • Wide-field operation removes the spatial focusing and therefore inside the focal volume illumination field is only temporally focused. This temporal focusing is achieved because different colors are spatially separated, i.e. the effect of geometrical dispersion.
  • the system 200 illustrated in FIG. 5 can be used to implement this concept.
  • the system 200 includes a grating 202, cylindrical collimating lens 204 and an objective lens 206 as in the system 100 of FIG. 2, but also included a grating pair 208 or a prism pair 210.
  • the axial position of the maximum signal excitation plane shifts to the position where the input spectrum chirp is canceled by the geometrical dispersion, i.e. the position where the pulse temporal width is shortest.
  • the formula that relates the input chirp and the shift of the maximum signal excitation plane can be obtained for Gaussian profiles.
  • FIG. 6 illustrates a modified version of the system 200 of FIG. 5 for implementing this application in which the output pulsed beam from a Ti/Sapphire laser 212 is passed through a lens into a single-core fiber 216, and then through another lens 218 to the grating 202.
  • the fiber-delivery of ultrashort pulses is immune to the fiber chromatic dispersion. This is true because the simultaneous spatial and temporal focusing technique intrinsically inherits the geometrical dispersion into the system as a result of wavelength spatial separation. The fiber dispersion will be automatically compensated by shifting the temporal focal plane away from the geometrical optics one. Using the Gaussian profile, the maximum pulse temporal width broadening that can be allowed without pre-dispersion compensation obeys the equation:
  • ⁇ R is the Raleigh length inside the focal volume corresponding to width of the rainbow

Landscapes

  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)

Abstract

L'invention porte sur une technique de focalisation simultanée spatio-temporelle d'impulsions de l'ordre de la femtoseconde qui améliore le rapport signal-bruit de fond dans l'imagerie multi-photons. Pour cela, on effectue une séparation spatiale des composants spectraux des impulsions en un 'faisceau arc-en-ciel' et on recombine ces composants au niveau du foyer spatial d'un système d'imagerie. La largeur d'impulsion temporelle devient une fonction de la distance, la largeur d'impulsion la plus courte étant confinée au foyer spatial. La technique peut considérablement améliorer le confinement spatial et réduire l'excitation de bruit de fond en microscopie multiphotons et, par conséquent, augmenter la profondeur d'imagerie dans le cas de spécimens biologiques à haute dispersion.
EP06736409A 2005-03-01 2006-03-01 Focalisation simultanee spatio-temporelle d'impulsions de l'ordre de la femtoseconde Withdrawn EP1864180A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US65690105P 2005-03-01 2005-03-01
PCT/US2006/007088 WO2006093962A2 (fr) 2005-03-01 2006-03-01 Focalisation simultanee spatio-temporelle d'impulsions de l'ordre de la femtoseconde

Publications (1)

Publication Number Publication Date
EP1864180A2 true EP1864180A2 (fr) 2007-12-12

Family

ID=36941733

Family Applications (1)

Application Number Title Priority Date Filing Date
EP06736409A Withdrawn EP1864180A2 (fr) 2005-03-01 2006-03-01 Focalisation simultanee spatio-temporelle d'impulsions de l'ordre de la femtoseconde

Country Status (3)

Country Link
US (1) US20080151238A1 (fr)
EP (1) EP1864180A2 (fr)
WO (1) WO2006093962A2 (fr)

Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9545689B2 (en) * 2010-03-31 2017-01-17 Colorado School Of Mines Spatially chirped pulses for femtosecond laser ablation through transparent materials
US20140313315A1 (en) * 2011-11-15 2014-10-23 Technion Research & Development Foundation Limited Method and system for transmitting light
CN103673891B (zh) * 2013-11-21 2016-05-18 清华大学 一种光栅外差干涉自准直测量装置
US10317390B2 (en) * 2014-09-08 2019-06-11 University Of Vienna Recording dynamics of cellular processes
US10007100B2 (en) * 2014-11-04 2018-06-26 Olympus Corporation Light sheet illumination microscope and light sheet illumination method
US10207365B2 (en) 2015-01-12 2019-02-19 The Chinese University Of Hong Kong Parallel laser manufacturing system and method
CN106124369B (zh) * 2016-06-08 2018-10-16 浙江大学 一种紧凑式全场彩虹测量探头
JP2018169502A (ja) * 2017-03-30 2018-11-01 オリンパス株式会社 顕微鏡装置
CN109211855B (zh) * 2018-08-10 2021-11-16 国家纳米科学中心 多光束多光子显微成像装置
EP3849451A4 (fr) 2018-09-10 2022-06-08 Treiser, Matthew, David Système laser délivrant des impulsions ultracourtes le long de multiples trajets d'émission de faisceau
CN109799602A (zh) * 2018-12-24 2019-05-24 清华大学 一种基于线扫描时空聚焦的光显微成像装置及方法
US11921273B2 (en) 2020-10-30 2024-03-05 Electronics And Telecommunications Research Institute Two-photon excited fluorescence microscope for diagnosis of Alzheimer's disease (AD) and mild cognitive impairment (MCI), and pulse compressor including therein
US11884009B2 (en) 2020-11-16 2024-01-30 The Chinese University Of Hong Kong 3D nanofabrication based on hydrogel scaffolds
CN113916855A (zh) * 2021-09-29 2022-01-11 深圳大学 一种显微成像装置
CN114721085B (zh) * 2022-04-13 2024-05-07 长飞光坊(武汉)科技有限公司 一种超快激光加工光纤光栅的焦点定位系统

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3873825A (en) * 1973-05-09 1975-03-25 Bell Telephone Labor Inc Apparatus and systems using broad band radiation pulse source
US5644429A (en) * 1992-07-23 1997-07-01 Research Foundation Of City College Of New York 2-dimensional imaging of translucent objects in turbid media
US5738101A (en) * 1996-01-18 1998-04-14 The Regents Of The University Of California Optical imaging through turbid media with a degenerate four-wave mixing correlation time gate
US6005256A (en) * 1998-02-12 1999-12-21 Raytheon Company Method and apparatus for performing cell analysis based on simultaneous multiple marker emissions from neoplasia (CASMMEN)
NZ510096A (en) * 1998-08-21 2003-02-28 Surromed Inc Confocal scanning system having spot excitation scanner and light detectors
US6795199B2 (en) * 2001-07-18 2004-09-21 Avraham Suhami Method and apparatus for dispersion compensated reflected time-of-flight tomography
JP4102180B2 (ja) * 2002-12-20 2008-06-18 浜松ホトニクス株式会社 高速粒子発生方法及び高速粒子発生装置
US7447408B2 (en) * 2004-07-02 2008-11-04 The General Hospital Corproation Imaging system and related techniques
JP5547868B2 (ja) * 2004-09-14 2014-07-16 イエダ リサーチ アンド ディベロップメント カンパニー リミテッド 顕微鏡系およびこれを用いた方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2006093962A3 *

Also Published As

Publication number Publication date
WO2006093962A2 (fr) 2006-09-08
US20080151238A1 (en) 2008-06-26
WO2006093962A3 (fr) 2008-05-15

Similar Documents

Publication Publication Date Title
EP1864180A2 (fr) Focalisation simultanee spatio-temporelle d'impulsions de l'ordre de la femtoseconde
Castello et al. A robust and versatile platform for image scanning microscopy enabling super-resolution FLIM
US9201008B2 (en) Method and system for obtaining an extended-depth-of-field volumetric image using laser scanning imaging
US9721326B2 (en) Method and system for improving resolution in laser imaging microscopy
Durst et al. Simultaneous spatial and temporal focusing in nonlinear microscopy
US9500846B2 (en) Rapid adaptive optical microscopy over large multicellular volumes
DE102006056429B3 (de) Lasermikroskop mit räumlich trennendem Strahlteiler
US20200150446A1 (en) Method and System for Improving Lateral Resolution in Optical Scanning Microscopy
Isobe et al. Enhancement of lateral resolution and optical sectioning capability of two-photon fluorescence microscopy by combining temporal-focusing with structured illumination
US11143555B2 (en) Methods and devices for reducing spectral noise and spectrometry systems employing such devices
Doi et al. High-resolution imaging in two-photon excitation microscopy using in situ estimations of the point spread function
Choi et al. Improving femtosecond laser pulse delivery through a hollow core photonic crystal fiber for temporally focused two-photon endomicroscopy
Conkey et al. High power, ultrashort pulse control through a multi-core fiber for ablation
US11041760B2 (en) Optical measurement device and optical measurement method
US7847933B2 (en) Cars microscopy and spectroscopy using ultrafast chirped pulses
Yushkov et al. AOTF-based hyperspectral imaging phase microscopy
US11604144B2 (en) Total internal reflection enabled wide-field Coherent anti-Stokes Raman scattering microscopy
Choi et al. Depth resolved hyperspectral imaging spectrometer based on structured light illumination and Fourier transform interferometry
Rózsa et al. Random access three-dimensional two-photon microscopy
CN111630432A (zh) 声光的装置和方法
Isobe et al. Temporal focusing microscopy combined with three-dimensional structured illumination
Zheng et al. Vibrational phase imaging in wide-field CARS for nonresonant background suppression
WO2016189095A1 (fr) Appareil permettant de former une image d'au moins un objet
Krishnamachari et al. Detecting lateral interfaces with focus‐engineered coherent anti‐Stokes Raman scattering microscopy
Chen et al. Holography-based structured light illumination for temporal focusing microscopy

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20070927

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL BA HR MK YU

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: CORNELL RESEARCH FOUNDATION, INC.

RIN1 Information on inventor provided before grant (corrected)

Inventor name: XU, CHRIS

Inventor name: ZHU, GUANGHAO

DAX Request for extension of the european patent (deleted)
RIC1 Information provided on ipc code assigned before grant

Ipc: G02B 5/28 20060101ALI20080602BHEP

Ipc: H04J 14/02 20060101ALI20080602BHEP

Ipc: G01B 11/24 20060101ALI20080602BHEP

Ipc: G01J 3/30 20060101ALI20080602BHEP

Ipc: G02B 1/10 20060101ALI20080602BHEP

Ipc: G02B 27/46 20060101ALI20080602BHEP

Ipc: G02B 27/44 20060101ALI20080602BHEP

Ipc: G02B 27/10 20060101AFI20080602BHEP

RIN1 Information on inventor provided before grant (corrected)

Inventor name: ZHU, GUANGHAO

Inventor name: XU, CHRIS

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20101001